X-ray tube.



I S. TOU-SEY.

X-RAY TUBE. APPLICATION FILED FZEB.23, 1911.

1,100,07, Patented June 16,1914

Inventor.- W7C 17M AS'IQnCZaL'r 272114533,

smcnam TousiiY', F. YORK, N. Y.

xiainr' wa Specification of Letters Patent.

PatentedJune 16.1914.

Application filed February 23, 1911. Serial No. 610,341.

To all whom it may concern Be it known that I, SINCLAIR TOUSEY, citizen of the United States,'resid1ng at .New York, N. Y., have invented certain new and useful Improvements in X-Ray Tubes,0f whichfthe following is a specification;

My invention has reference to X-ray tubes and its object is to'secure better definition of the object being viewed or photographed. This is accomplished by utilizing only the direct rays coming from a very small point on the anode (anticathode) but without restricting the area of illumination While at the same time avoiding the action of secondary rays which, in X-ray tubes as ordinarily constructed blur the image-by producing a penumbra. 4

l'he invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawings forming a part of this specification, with the understanding, however, that the drawings are largely indicative and that the invention is not limited to the exact showing of the drawings.

In the drawings: Figure 1 is a longitudinal section of. an X-ra tube in which the wall is made of a materlal givingrise to few secondary rays. Fig. 2 is a similarview showing one form and arrangement of screens.' f v Referrin to the drawings there is shown a common orm of X-ray tube provided with a cathode f and an anode or anticathode F, of which latter the'focus point is indicated by w. Generally the cathode and anode may be constructed, in the usual man-.

ner and a regulator of the degree of vacuum ma beprovided as is customary.

1 1 1 the form shown in Fig. 1- the wall-outside an area a, b, may be made of lead-glass or of any suitable material suilici'ently opaque to X-rays whether primary orsecondary to reduce the amount transmitted to a negligible quantity. The area a, I), however, is made of amaterial transparent to X-rays and gives rise to so few. secondary rays that they will not appreciably blur the. image. The area ar b on thewall of the tube may be of any desired sine and shape.

The lines zv-A and wB in Fig. l, indicatethe outline of a cone of active rays passing through the area a--b of the Wall ofthe tube and 0 indicates the object to be I photographed or observed, lying within the cone of X-rays.

If A-B be assumed to be the photographic plate and A-m-B the cone of rays acting on the object O properly positioned with reference to the plate A.B, then the image 0 of the object 0 will be projected upon the plate without apparent penumbra. The same efl'ect may be produced by coating the tube, except at the area ab, with a material opaque to X-rays or by a diaphragm placed near the walls of the tube.

In Fig. 2,,the screen S, S, is extended soas to almost completely cover the front surface of the anode to interrupt all radiations except the utilized X-rays to-which it is transparent. opening 6 toward the cathode for the passage of the cathode stream and may be open at the edges for the escape of heat. This screen may be supported by and insulated from the anode supporting stem or may be otherwise supported. Fig. 2, no diaphragm is needed.

The screen S may be made of, aluminum "or other suitable substance transparent to the direct X-rays from the focus point of the anode but is resistant to other radiations from the front surface'of the anode, which other-radiations cause secondary rays by their impact with the glass wall of the tube. :The only portion of such undesirable rays which escape with full force are those directed toward the cathode where they a'reof lit'-' It is. provided with an In the structure of.

said anode stem, said screen having an aper- In testimony whereof, I ai'fix my signature ture therein toward the cathode for the pasin presence of two witnesses.

sage of the cathode stream and being so po- SINCLAIR TOUSEY. sitioned around the anode as to intercept Witnesses: 6 secondary radiations from the front face W; C. HUTTON,

thereof, substantially as described. T. YNULSEN. 

